1. Field of the Invention
The present invention relates to a trough device in a soldering furnace, and particularly to a trough device, which is disposed in a soldering furnace and is attached with a soldering pot in conjunction with a transmission device so as to enhance the soldering job on a circuit board.
2. Description of Related Art
Referring to FIGS. 1 to 3, a trough device A in a conventional soldering furnace comprises a transmission shaft A1, a soldering pot A2, a screen plate A3, a guidance part A4, a fan blade part A5, a trough part A6, and a motor A7. The transmission device A1 provides a support frame A11 to hold the transmission shaft A1 and the transmission shaft passes through the fan blade part A5 to engage with the bottom of the soldering pot A2 by way of a nut A12. A transmission belt A71 is disposed between to connect with the transmission shaft A1 and the motor A7 so that the transmission shaft A1 can be driven by the motor A7. The tin solder in the trough part A6 is heated up by the heater A61 and is melted into liquid tin solder. Then, the liquid tin solder is sent to the screen plate A3 through the soldering pot A2 by the traction of the fan blade part A5 and reaches to the guidance part A4. Finally, the liquid tin solder overflows the guidance part A4 to perform the soldering job on a circuit board B. The conventional device has the following shortcomings:
1. The circuit board B moves forward with an inclining angle D of 3xcx9c7xc2x0 as shown in FIG. 3, however, the tin solder overflows the guidance part A4 horizontally and only a small part of area on the circuit board B touches the tin solder such that it results in an uneven soldered surface on the circuit board B.
2. Although the working table carrying the circuit board B can be adjusted to have a higher elevation for shortening the distance between the circuit board and the guidance part A4, it is required to consider if the working table van be kept flat after the working table being adjusted. An improper adjustment for the working table may cause an uneven soldered surface on the circuit board and it is easy to become short circuit. Further, it is much tedious if the working table is raised the height thereof.
3. The fan blade part A5 usually provides a high rotational speed and it is insufficient for the support frame A1 with the nut A12 to hold the transmission shaft A1 and the fan blade part A5. Hence, the axis of the transmission shaft A1 may become deviated and the fan blade part A5 may become loosely after a period of running.
4. The components of the transmission device are arranged to expose to the outside and the tin solder is sprayed with a very high speed so that it is easy for the tin solder to stay in the clearances between the components and the life span of components may be shortened.
5. The transmission device is hard to be set up or detached so that it is not favorable for the maintenance work.
A trough device in a soldering furnace according to the present invention comprises a motor, a soldering pot, support device, a trough part and transmission device. The support device connects with a fixing base of the motor via a micro adjustment device and an inclinometer for adjusting an inclining angle of the soldering pot and informing the adjusted inclining angle. A guidance part with double layer structure is located at the soldering pot and can receive the tin oxide residue falling down from the circuit board or spattered out from the soldering pot to prevent the oxide tin residue from flowing back to the trough part. The transmission device further comprises a transmission shaft, a shaft hub, a fan blade part and fixing plate assembly. The shaft hub surrounds the transmission shaft with bearings being disposed between the shaft hub and the transmission shaft. The fixing plate assembly is arranged at the lower end of the shaft hub and engages with the soldering pot by way of screw threads. The transmission shaft, the shaft hub, the fan blade part, and the fixing plate assembly can be fixed coaxially with being supported firmly by the shaft hub and the fixing plate assembly so that the transmission shaft can rotate more steadily and the components in the transmission device can be free from being contaminated by the tin solder.
A primary object of the present invention provides a trough device in a soldering furnace, in which the soldering pot can be turned an inclining angle to the right and the reversed directions with a support device so that the timing of the tin solder overflowing the guidance part can be extended from the solder disengaging point of the circuit board to the solder wave. Hence, it is not possible for the pin legs on the circuit board to connect with each other so that it is unable to result in short circuit.
Another object of the present invention provides a trough device in a soldering furnace, in which the guidance part thereof may have an output adjustable plate to adjust the amount of tin solder flowing out from the guidance part properly so as to expand the contact area of the circuit board more evenly.
A further object of the present invention provides a trough device in a soldering furnace, in which a micro adjustment device and a inclinometer can indicate the inclining angle of the soldering pot automatically.
A further object of the present invention provides a trough device in soldering furnace, in which the guidance part has a double layer structure to refrain the oxide tin solder from flowing back.
A further object of the present invention provides a trough device soldering furnace, in which the transmission shaft is surrounded by a shaft hub and is fixed to a fixing plate assembly at the lower end thereof so that the transmission shaft can rotate more steadily with support of the shaft hub and the fixing plate assembly.
A further object of the present invention provides a trough device in a soldering furnace, in which the transmission shaft is surrounded by a shaft hub to avoid the tin solder staining the transmission shaft and other components so as to prolong the life span of the trough device.
A further object of present invention provides a trough device in the soldering furnace, which is simple for maintenance.